The above-described type of traveling transmission has been well known, as disclosed in JP-A 2000-352446. In a transmission disclosed in the above publication, a pair of auxiliary transmissions, i.e., a front-back travel selector device and a high-low speed selector device are interposed between a main clutch and a multi-speed-stage mechanical transmission.
However, in the conventional transmission, the auxiliary transmission is kept in a transmission state when the main clutch is disengaged during a speed change operation by the mechanical transmission. With the above configuration, inertial rotation is continued in the auxiliary transmission when the main clutch is disengaged, thereby applying an inertial mass of the auxiliary transmission to the mechanical transmission. Therefore, there has arisen an inconvenience that a time is required for the speed change operation in the mechanical transmission, or that a gear shift shock or an abnormal noise occurs in the mechanical transmission.
One object of the present invention is to provide a novel traveling transmission for a working vehicle without raising those problems experienced in the conventional art.